Total Testosterone

What is total testosterone?

Testosterone is the most important of the male sex hormones known as androgens. In men, most of it is produced in the testes; in women, smaller amounts are produced in the ovaries and adrenal glands. In men, it plays a role in sperm production, muscle and bone mass, sex drive and the development of male characteristics such as beard growth; in women, it plays a role in sex drive and bone health. In boys, changes during puberty such as the deepening of the voice and muscle development also largely occur under the effect of this hormone.

Most testosterone in the blood circulates bound to proteins called SHBG and albumin, while a small portion is free. The total testosterone test measures the sum of the bound and free portions and is the first-step test in assessing testosterone. The measurement is usually done with immunological methods; at low levels, such as those found in women and children, more sensitive methods may be needed.

When is the total testosterone test ordered?

In men, this test is most often ordered for complaints that suggest testosterone deficiency, and in women for signs of excess male hormones. In children, early or late onset of puberty is also among the uses of the test. In men receiving testosterone treatment, it is repeated at regular intervals to monitor whether the hormone level is within the target range.

• Low sex drive and erection difficulties
• Investigation of infertility in men
• Muscle loss, fatigue and osteoporosis
• Increased hair growth, acne or hair loss in women
• Menstrual irregularity and suspected polycystic ovary syndrome
• Monitoring testosterone treatment

How do you prepare for the total testosterone test?

Testosterone is at its highest in the morning, especially in men, and decreases as the day goes on. For this reason, it is recommended to give blood early in the morning after an overnight fast; the value may drop temporarily after a meal. A low result is usually confirmed by repeating the test on another morning. Because a sleepless night, strenuous exercise or a recent illness can also temporarily lower the value, try to keep to your usual routine before giving blood.

For women, your doctor may ask for the sample to be taken, for example, in the first days of the menstrual cycle. Birth control pills, testosterone or other hormone treatments, cortisone and strong opioid-type painkillers can affect the result; if you are receiving testosterone treatment, plan the timing of the blood draw with your doctor. High-dose biotin can also change the result with some methods. Having your blood sample taken by a nurse at your home in the morning makes it easier to meet the fasting and timing requirements.

What does the total testosterone result mean?

In men, low total testosterone may indicate hormone deficiency (hypogonadism) originating in the testes or the pituitary gland. Obesity, type 2 diabetes, sleep disorders, serious illnesses and certain medicines can also lower the value, and there is a slow decline with age. In men, a high value is most often associated with the use of external hormones or anabolic steroids.

In women, high testosterone is most commonly seen in polycystic ovary syndrome; when the elevation is marked and symptoms develop rapidly, rare causes originating in the adrenal glands or ovaries are investigated. Because changes in SHBG level can make the total value misleading, your doctor may also order a free testosterone or SHBG measurement. The reference range differs considerably by sex, age and laboratory; this page shows the laboratory's separate ranges for men and women. Your doctor, who evaluates your symptoms and other test results together, should interpret what the result means for you.